3G is a third-generation mobile communications technology, and is a cellular mobile communications technology supporting high-speed data transmission. Long Term Evolution (LTE) is a new generation mobile communication standard developed by the 3rd Generation Partnership Project (3GPP). Compared with other communication standards, LTE has a higher transmission rate and better transmission quality, and currently becomes a popular communication standard. An existing fourth-generation mobile communications technology (4G) may include two standards, time division LTE (TD-LTE) and frequency division duplex LTE (FDD-LTE).
Two subscriber identity module (SIM) cards may be simultaneously inserted in a dual SIM mobile phone, and the two cards are both in standby mode. However, in existing dual SIM mobile phones, only one SIM card can support 3G or 4G services, and the other SIM can only support second generation (2G) services. Therefore, in the existing dual SIM mobile phones, the two SIM cards cannot simultaneously support 3G or 4G services.